Not really, they usually fail fairly suddenly in my experience. Lost a few that way. I eventually went to a electric pump to replace on my T/A, but the noise was excessive, so I went back. But the electric wasn't enough to pump fuel to my tame 455 and it would leanout at WOT around 1/4 mile into the run. The mechanical pump is a good piece, but being next to the engine caused my 455 fuel overheating, and the electric cured that.
160K and factory pump, not a bad idea to replace to keep reliability up. My 76 Olds failed the factory pump around 80K miles, and promptly lunched the ignition module in the process (no idea the connection on that one). Years later the float decided not to anymore and flooded the engine, also lunching the ignition module again. Again, no clue why, it just did. These were early GM modules so maybe there was some quality issues there.
No real symptoms except maybe hard starting or lean out when at lower rpm, then leading engine stall.
It took my a while on my 307 brougham because of all the stuff you have to move out of the way to get to it. Not a hard job, just time consuming. Especially when you have to do it when it is 32 F and the car is outside.